1. Field of Invention
The present invention relates to a micro-electro-mechanical system (MEMS) module which includes a MEMS die stacked on an electronic circuit die. The electronic circuit communicates with the MEMS device and outside the module through a trough-silicon via (TSV).
2. Description of Related Art
MEMS devices are commonly used nowadays, for sensing motions, pressures, etc. Typical MEMS devices include accelerometers, gyro sensors, altitude sensors, acoustical sensors, etc. The sensed result by a MEMS device is read out by an electronic circuit. In one type of architecture, a MEMS device and an electronic circuit are separately manufactured as two dies and packaged into one MEMS module.
FIG. 1 shows a conventional MEMS module, in which a MEMS die 11 is stacked on an electronic circuit die 12. This conventional structure can reduce the size of the package, but it has at least the following drawback: Because the MEMS die 11 communicates with the electronic circuit die 12 at the interfacing location where they are stacked together, it requires high alignment precision between the MEMS die 11 and the electronic circuit die 12.
FIG. 2 shows a conventional MEMS package 20 which is disclosed by U.S. Pat. No. 8,610,272. The MEMS package 20 includes a MEMS device 21, wirings 23, a bottom package layer 24, and solder balls 24. The MEMS device 21 is electrically connected to the solder balls 24 through the wirings 23, and the solder balls 24 electrically connect the MEMS package 20 to an external electronic circuit (not shown). This conventional structure does not integrate an electronic circuit in the package, so it is required to package the electronic circuit and electrically connect the MEMS package 20 and the packaged electronic circuit; obviously, the total size of two packages is hard to reduce.
FIG. 3 shows a conventional electronic circuit package 30. In order to avoid connecting a wiring on top of the circuit device 32 so as not to increase the thickness, the circuit device 32 is connected to a bottom substrate 300 which includes TSVs 36 so that the circuit device 32 can communicate with outside. A number of wirings 33 electrically connect the top of some of the TSVs to other circuit devices 37. In this structure, the circuit devices 37 are located at the lateral sides of the bottom substrate 300, which increases the total area of the package.
FIG. 4 shows a conventional electronic circuit package 40. Two circuit devices 42 and 47 are provided, which are respectively electrically connected to bottom substrates 400 and 410 through wirings from top of the circuit devices 42 and 47. The bottom substrate 400 includes TSVs 46. The circuit devices 42 and 47 communicate with each other through solder balls 45; they communicate with outside through solder balls 450. In comparison with the prior art of FIG. 3, the thickness of the electronic circuit package 40 is much larger because of the wiring connecting the top of the circuit device 42.
Furthermore, the prior arts shown in FIGS. 3 and 4 do not explicitly teach packaging a MEMS die and an electronic circuit into one module.
The aforementioned prior arts have the drawback that they do not provide a small size MEMS module with electronic circuit integrated therein, or, if a small size MEMS module is provided, it requires high alignment precision. In view of the above, the present invention provides a small size MEMS module which does not require high alignment precision, to solve the problem of the prior arts.